Puffer fish release the 'drug' when they get nervous, and dolphins have worked out how to make it happen - by passing them around like a toy

Dolphins deliberately get high by targeting puffer fish, chewing them a little, and passing them round.

The victims release a powerful toxin when they are nervous which can be deadly in large doses, but if taken in small amounts, makes the dolphins go into a narcotic state.

The scenes were filmed for BBC documentary Dolphins: Spy in the Pod and show the clever fish pass their prey around like a toy while taking in the 'drug'.

The documentary was filmed by award-winning wildlife documentary producer John Downer.

Rob Pilley, a zoologist who helped produce the series, told the Sunday Times: “After chewing the puffer gently and passing it round, they began acting most peculiarly, hanging around with their noses at the surface as if fascinated by their own reflection.

“It reminded us of that craze a few years ago when people started licking toads to get a buzz, especially the way they hung there in a daze afterwards. It was the most extraordinary thing to see.”

A spy camera was hidden in a fake turtle which could submerge and watch the dolphins' activity.

It will feature in the second episode of the series, which starts on BBC One on Thursday at 8pm.